how much brighter are the MBP screens than the MB screens?

In an effort to decide if the MB is right for me going foward, or a MBP, I'd like to find out how much brighter the screens are on the MBP than the MB. Side by side, it looks about 10-20%. Are there any more objective tests to be found?

I think notebookcheck.com has reviews of both Macbook and MBP models with objective brightness measurement. However, Apple sacrificed everything else to get brightness so, as iwoot suggested, it really doesn't say much about the quality of the display.

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